This grant is targeted towards the PI's long-term focus to characterize the structure and function of the midgut of mosquitoes. This grant focuses upon elucidating the molecular processes involved in nutrient uptake in Aedes aegypti. Through a molecular approach to identify transport processes at the midgut, the PI has isolated cDNA's for 3 amino-acid transporters, a potential protein needed to form a functional heterodimer with the amino acid transporters, and a putative sucrose transporter from the midgut of Aedes aegypti. In objective 1, the PI proposes to continue in the isolation of full-length cDNA clones for two of the proteins for which he has partial cDNAs. These cDNAs will be expressed in a heterologous expression system (Xenopus oocytes) and this system used to characterize the substrate selectivity of each of the amino acid transporters and the ion selectivity of the transport process. In the second objective, similar experiments will be performed for the sucrose transporter. As the final objective, the in vivo regulation of these transporters will be analyzed. The expression of the genes will be analyzed in vivo to determine if there is developmental regulation and modulation following either sugar or blood feeding.